This invention relates to a process for the liquefaction of carbonaceous solid fuels, particularly coals, enhanced with respect to the production of asphaltene-rich solvent refined coal wherein the recycle stream passed back to the slurry mix tank contains a predominant amount of preasphaltenes and solid residue in the near or relative near absence of asphaltenes to mitigate the amount of total hydrogen consumed in the process.
This process is directed to the liquefaction of a coal material to prepare, as a product of the process, an asphaltene-rich solvent refined coal, which may be hydrotreated to different products. Many such processes have been directed to such solvent refinement of coal in the presence of a hydrogen donor. This process is different from the prior art in re the type and content of the recycle stream passed from a solvent deashing zone to the slurry mix tank. This recycle stream is a predominant preasphaltene and solid residue stream, which is antithetical to the prior art which normally transfers in the recycle stream from a critical solvent deashing zone either asphaltenes, or hydrotreated asphaltenes with distillate product in admixture therewith, to the slurry mix tank. In such a liquefaction process the heating and the liquefaction of the coal yields light gases and a slurry which is further processed by vacuum distillation to produce a light distillate product, a recycle solvent, and a heavy fraction having residual solvent, dissolved coal products, undissolved minerals and ash materials plus unconverted coal macerals.